This invention relates to an image processing selecting method, an image selecting method, and an image processing apparatus for processing a radiation image, and in particular, to an image processing selecting method, an image selecting method, and an image processing apparatus which are capable of selecting an optimum processing condition for a radiation image.
In recent years, an apparatus capable of radiographing a radiation image directly as a digital image has been developed. For example, for an apparatus which detects the amount of radiation applied to a radiography object (subject) and obtains a radiation image formed corresponding to the detected amount as an electrical signal, a number of methods in which a detector using a stimulable phosphor is employed have been disclosed in the publications of unexamined patent application S55-12429, S63-189853, etc.
In such an apparatus, radiation which has once transmitted through a radiography object is applied to a detector having a stimulable phosphor layer bonded on its sheet-shaped substrate by coating or vapor deposition, and is absorbed by the stimulable phosphor layer. After that, by stimulating this stimulable phosphor layer by light or heat energy, the radiation energy accumulated in this stimulable phosphor layer through the above-mentioned absorption is emitted as a fluorescent light, and this fluorescent light is photoelectrically converted, to obtain an image signal.
On the other hand, it has been proposed an apparatus for detecting radiation image which is obtained by generating charge corresponding to the intensity of the applied radiation in a photoconductive layer, accumulating the generated charge in a plurality of capacitors arrayed two-dimensionally, and taking out the accumulated amounts of charge.
In such a radiation image detector, what is called a flat-panel detector (an FPD) is used. For an FPD of this kind, as described in the publication of unexamined patent application H9-90048, it has been known what is actualized by the combination of a phosphor emitting fluorescent light in accordance with the intensity of the radiation applied and a photoelectric conversion device such as a photodiode array or a CCD sensor which performs photoelectric conversion by receiving the fluorescent light emitted by the phosphor directly or through a reduction optical system. Further, a similar FPD is noted in the publication of unexamined patent application H6-342098.
In such an apparatus, in order to express a radiation image in a gradation suitable for diagnosis, it is desirable to make a gradation conversion automatically for the image obtained by such an apparatus as mentioned in the above in a manner such that a medical doctor can easily observe the portion to be watched (interest region).
In order to carry out such an automatic gradation conversion, it is done to determine the processing condition from the statistical feature of the image data (the maximum value, minimum value, histogram, etc. of the data) to apply image processing to the whole image.
Further, in order to make the structure of minute portions easy to observe, edge enhancement processing is carried out, and dynamic range compression processing for narrowing the signal range of the radiography object to make both of the portion of high density and the portion of low density simultaneously easy to observe, etc. are also done.
However, in a radiography to be utilized in diagnosis, the body part becoming the radiography target is diversified from the head to limbs, and because the region to be watched by a medical doctor is different for each case, the image processing condition for obtaining an image which is most suitable for diagnosis becomes different for each radiography body part. Further, in the same way, the processing condition becomes different also in accordance with the radiographing orientation (the radiographing direction) in which the radiography object is placed.
For that reason, heretofore, in these apparatus, it is necessary to input the radiographed body part of the radiography object, the radiographing orientation, etc. before carrying out image processing in order to select the most suitable condition.
In some hospitals, there are provided a hospital information system (HIS) or a radiology information system (RIS), and the information on the radiographed body part can be obtained directly from the order information for the radiographing; therefore, without a special operation of a radiologist, the selection of the optimum processing condition is possible; however, because in many hospitals, there is provided no such system, it is necessary for a radiologist or some one like that to input these bits of information manually.
Further, in a radiographing in an emergency, in order to carry out it rapidly, in some cases a radiologist or the other person manually inputs the information on the body part of an radiography object etc. even in the hospitals provided with the above-mentioned HIS or RIS.
However, there are more than one hundred kinds of body parts to be generally radiographed, and it is troublesome to make the above-mentioned manual input operation every time when radiographing is carried out, which has been a burden for radiologists who carry out radiographing.
Therefore, in order to lighten the burden for radiologists, it has been required to select the optimum processing condition easily for a radiographed image.